@modelcontextprotocol/client

MCP TypeScript SDK v2 Client by Model Context Protocol

Model Context Protocol implementation for TypeScript - Client package

Live Registry Versionv2.4.0Previous: v2.3.1Published 2026-10-23

Stability Grade

B (78/100)

90-Day Velocity

5 releases

Moderate cadence

Dependencies

7 direct

NPM manifest

License

Apache-2.0

Verified on NPM

Recommended Exact Pin: npm install @modelcontextprotocol/client@2.4.0

NPM Registry ->GitHub Repo ->

TL;DR Verdict & Quick Citation Summary (2026-10-27)Source: AgentBreakWatch Live NPM Index

MCP TypeScript SDK v2 Client (@modelcontextprotocol/client) is currently at v2.4.0 on NPM (published 2026-10-23), with a 90-day stability score of 78/100 (B) and HIGH schema drift risk across 5 releases in the past 90 days. v2 split of @modelcontextprotocol/sdk. Since 2.4.0 the client does not list tools that put x-mcp-header on a number parameter, and outputSchema results built from z.object().meta({ id }) arrive unwrapped in structuredContent on 2025-11-25 connections. Production teams should pin npm install @modelcontextprotocol/client@2.4.0 rather than using unpinned @latest tags.

Breaking Changes & Tool Schema Drift Analysis

v2 split of @modelcontextprotocol/sdk. Since 2.4.0 the client does not list tools that put x-mcp-header on a number parameter, and outputSchema results built from z.object().meta({ id }) arrive unwrapped in structuredContent on 2025-11-25 connections.

Watched Exports / MCP Tool Signatures:

ClientlistToolscallToolstructuredContentOAuthClientProvider

Before (Deprecated / Unpinned Pattern)

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
const value = result.structuredContent.result;

After (Verified v2.4.0 Pattern)

import { Client } from "@modelcontextprotocol/client";
const value = result.structuredContent;

Frequently Asked Questions: @modelcontextprotocol/client

What is the latest version of @modelcontextprotocol/client on NPM?

As of 2026-10-27, the latest stable version of @modelcontextprotocol/client (MCP TypeScript SDK v2 Client by Model Context Protocol) on NPM is v2.4.0, published on 2026-10-23. It has shipped 5 releases in the last 90 days.

Does @modelcontextprotocol/client v2.4.0 have breaking changes or MCP schema drift risk?

@modelcontextprotocol/client currently carries a HIGH schema drift risk rating with a Stability Score of 78/100 (Grade B). v2 split of @modelcontextprotocol/sdk. Since 2.4.0 the client does not list tools that put x-mcp-header on a number parameter, and outputSchema results built from z.object().meta({ id }) arrive unwrapped in structuredContent on 2025-11-25 connections.

How do I safely pin @modelcontextprotocol/client in production?

Avoid unpinned @latest tags in production agent configs. Pin the exact verified version using `npm install @modelcontextprotocol/client@2.4.0` and monitor Client, listTools, callTool, structuredContent, OAuthClientProvider for parameter or schema changes.

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